There is growing interest in the use of OFETs, where an active channel of the transistor is made from an organic semiconductive material. The organic semiconductive material should be capable of supporting, under a broad range of environmental conditions, a channel of holes or electrons when the device is switched on. Ideally, the mobility of carriers in the channel is resistant to the environmental effects of elevated humidity.
Unfortunately, the performance of conventional p-type organic semiconductive materials is highly sensitive to moisture. Consequently, the mobility of holes in conventional p-type OFETs rapidly decreases with increased humidity. Previous attempts to reduce moisture sensitivity includes placing an encapsulating barrier layer over the semiconductor molecules. The use of a barrier layer, however, increases the expense and complexity to fabricate the OFET. Moreover, a barrier layer may not be desirable in applications where the organic semiconductor material serves as a sensor for the detection of target organic species in air or aqueous media.
The present invention overcomes the disadvantages associated with prior art devices by providing an OFET having a p-type channel composed of fluorinated organic semiconductor molecules with reduced sensitivity towards moisture, and a method for the fabrication of such a device.